page_title: Romeral Fault System
section_title: Description
hierarchical_section_title: Romeral Fault System / Description
caption_attribution_description: Relieve Valle del Cauca, Colombia
context_page_description: The Romeral Fault System is a megaregional system of major parallel and anastomosing faults in the Central Ranges of the Colombian Andes and the Cauca, Amagá, and Sinú-San Jacinto Basins. The system spans across ten departments of Colombia, from northeast to south Bolívar, Sucre, Córdoba, Antioquia, Caldas, Risaralda, Quindío, Valle del Cauca, Cauca and Nariño. The fault zone extends into Ecuador where it is known as the Peltetec Fault System. The in detail described part of the Romeral Fault System south of Córdoba has a total length of 697.4 kilometres with a cumulative length of 1,787.9 kilometres and runs along an average north to south strike of 017.6 ± 16, cross-cutting the central-western portion of Colombia.
  The fault system, active during more than 200 million years from the Triassic to recent, represents the ancient western continental margin of northwestern South America and forms the boundary between obducted oceanic crust to the west of the fault zone and continental crust to the east.
context_section_description: The megaregional Romeral Fault System represents the geological boundary between the Western and Central Ranges of the Colombian Andes. The fault system was active since the Triassic. During the Cretaceous, this was the western margin of northwestern South America. It is one of the most active and continuous fault systems in Colombia. It extends southward into Ecuador and is known there as the Peltetec Fault System. In the literature, several names have been applied to the fault system as it traverses the length of the country. The oldest name is the Guayaquil-Dolores Megashear, which involves a whole set of parallel fractures in western Colombia. The number of faults that comprise the width of the system ranges between three and five, depending upon location in the country. Near latitude 7° N, the fault system includes the Peque, Heliconia, Sabanalarga, and Cauca Occidental Faults, mainly in the department of Antioquia. Farther south, between about latitudes 1° and 5° N, the faults are known from north to south as the Pijao-Silvia, Quebradagrande, Potrerillos, Guabas-Pradera, Cauca-Almaguer, Rosas-Julumito, Popayán, Paispamba, El Rosal, and Buesaco Faults.
  The fault system with described segments totalling almost 700 kilometres (430 mi) in length comprises several parallel regional fractures (faults) that form the transition zone between oceanic rocks to the west and continental rocks to the east. The geology of the western domain consists of an ophiolitic belt with oceanic gabbroic, basaltic and sedimentary rocks of Cretaceous age. The eastern domain consists primarily of continentalised metamorphic schistose, oceanic, and continental rocks, mainly of Paleozoic age. The Romeral Fault System forms a 20 to 40 kilometres (12 to 25 mi) wide deformed belt that is parallel to the western slope of the Central Ranges of the Colombian Andes; it extends from the Gulf of Guayaquil in Ecuador in the south through Colombia to the Caribbean Sea in the north. At least one ancient subduction zone is believed to underlay some parts of the zone. Although this is the most studied fault system in Colombia, little is still known about its paleoseismic characteristics (most recent faulting, slip rates, and recurrence intervals). Parallel to the Romeral Fault System runs the Cauca-Pujilí Fault that also extends into Ecuador in the south. The two fault zones converge in the northern part of the Cauca Basin.
  The fault system is reverse sinistral (left lateral) in the northern part of the country, conspicuous to about latitude 5° N, from there south to Ecuador, it is mainly reverse-dextral (right lateral). The system forms prominent fault lines and well-developed fault scarps as much as 400 metres (1,300 ft) high on Pleistocene-aged sedimentary deposits, and eroded scarps on older Cretaceous to Paleozoic rocks. The system forms an outstanding break-in-slope above the easternmost parallel set of faults. The upper part of the easternmost major scarps forms the topographic divide of the Central Ranges of Colombia. Regional neotectonic features include linear valleys, offset drainages, aligned creeks, triangular facets, saddles, and L-shaped spurs and linear ridges. The fault offsets Quaternary volcanic rocks, alluvium and colluvium.
caption: The cities of Cali, situated in the valley of the Cauca River and Armenia, Pereira and Manizales in the adjacent mountainous areas are all affected by the movements of the Romeral Fault System with frequent smaller and occasional major earthquakes
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